Re: 1970 Evinrude 115 HP hydroelectric shift issue
I have been running the electric shift oil as recommended by my marina all last summer and will be replacing with new this week. When the previous owner got the boat the reverse did work, but he used regular lower unit oil and that is when the reverse quit working. I will have to seperate the lower unit and test the leads. I want to replace the water pump and can check it then. I have some time today and can open up the shift control box and check the leads inside too.
Salvage yards for a replacement solenoid is a bummer but will see if I can find one just in case. I ran the boat all last summer with no reverse using paddles to back out of the boat ramps but it would be nice to have it all working again. Thanks for all your replies and will check out the switch and report back.
You don't have to seperate the lower to check the leads, there should be knife connectors accessable in the rear of the engine housing.
(Hydro Electric Shift System Explained)
(J. Reeves)
The shifting setup of the lower unit is what's called a "Hydro Electric Shift", which is quite complex consisting of voltage being applied to solenoids in the lower unit which in turn change oil passages via a oil pump that supplies various pressure on a spring loaded shifter dog.
The wires leading to the lower unit (at the powerhead) are "Green" and "Blue". The engine must be running or cranking over in order to shift out of forward gear.
You CAN NOT use HI VIS lube in that lower unit. You MUST USE what OMC calls "Premium Blend" lube, commonly called "Type C". (A thinner lube)
Note: The engine must be running OR have the driveshaft turning by some other means in order for the engine to shift.
In neutral, you need 12v to the "Green" wire.
In reverse, you need 12v to both wires, the "Green" one and the "Blue" one.
In forward, there should be no voltage to either wire. (The spring loaded shifter dog forces the unit into forward gear)
To check the lower unit for proper shifting to make sure you have no trouble there, remove the spark plugs to avoid problems and to allow a higher cranking speed.
This next step eliminates the actual shift switch in case problems may exist there.... Disconnect the blue & green wires at the knife connectors (the rubber insulated boots) leading to the lower unit at the powerhead, then using jumpers, take voltage direct from the starter solenoid to apply voltage to the "Green" wire for neutral, then both wires 'Green" & "Blue" for reverse (Remember the engine must be cranking over in order to shift).
With no voltage applied, the unit should be in forward. No need for a ground jumper... the lower unit's already grounded. You may crank the engine with the key switch or by energizing the starter solenoid with a jumper wire.
